Smoke opacity meter
AssigneeParticulate Instruments
InventorDale F. Berndt
Life of this patent
Estimating the term…
Abstract
Apparatus for controllably admitting a sample volume of engine exhaust into a bifurcated, closed-loop opacity chamber and wherein the exhaust sample is controllably directed away from the internal optics via symmetric flow inducing air guides. A pulsed light source is controllably directed through the opacity chamber and exhaust sample and the detected light is compared to a reference level so as to determine a relative measure of the sample's opacity. Attendant control circuitry permits the selected display of corresponding sample opacity and density values.
Claims12
Apparatus for measuring the particulate content of air comprising:
- an elongated hollow chamber having at least one end mounted input port and at least one output port mounted along the length of said chamber;
- means for coupling sample quantities of particulate containing air to said input port;
- light source means for directing a beam of light from one end through said chamber and the air therein;
- light detector means mounted along said chamber beyond said outlet port in opposed relation to said light source means for detecting emanating light;
- means for establishing a pressure differential from said input port to said output port and directing air flow towards said output port and away from said light source means and said light detector means;
- and
- means responsive to detected light for measuring the particulate content of the sample air.
A photo-optic system for measuring the particulate content of air, comprising:
- means for coupling samples of particulate containing air to said system;
- a sample chamber having first and second inlet ports for receiving said particulate containing air samples;
- an outlet port mounted along said sample chamber between said first and second inlet ports and coupled to means for drawing the said sample air towards said outlet port;
- light source means open to the atmosphere and coupled to one end of said sample chamber for directing a collimated beam of light through said sample chamber and including means for detecting a portion of said light beam and producing a reference light signal;
- light detector means open to the atmosphere and mounted at an end of said sample chamber opposite to said light source means for producing a signal proportional to the amount of light emanating from said chamber relative to said reference light signal;
- and
- means responsive to said proportional signal over a sampling period for selectively determining either a normal opacity value, a value corresponding to the peak magnitude of the sensed opacity or an integrated opacity value, wherein the peak value is determined by means for continuously comparing and counting at a first clock rate each instance where the magnitude of said sensed signal for one clock cycle exceeds the magnitude of the previous clock cycle, and wherein the integrated value is determined by means for converting said sensed signal to a corresponding frequency and for continuously counting the frequency dependent signal and thereby the total particulate detected for the sampling period.
Dependencies are inferred from the claim text.